Patent Document 1 describes a LC composite component serving as a composite electronic component. The LC composite component is formed by jointing a part made of a dielectric material (hereinafter, this part is called the “dielectric body portion”) and a part made of a magnetic material (hereinafter, this part is called the “magnetic body portion”) via a part made of a specific material (hereinafter, this part is called the “intermediate part”). In the LC composite component, plural pairs of electrodes including conductive bodies are provided inside of the dielectric body portion, the dielectric body portion functions as a capacitor, a coil including a conductive body is formed inside of the magnetic body portion, and the magnetic body portion functions as an inductor.
The dielectric body portion of the composite electronic component described in Patent Document 1 is formed of a material of crystallized glass containing SiO2, Al2O3, CaO, and the like, the material containing Ni—Cu—Zn ferrite. Meanwhile, the magnetic body portion of the composite electronic component described in Patent Document 1 is formed of magnetic ferrite powder. Therefore, a thermal expansion coefficient of the dielectric body portion and a thermal expansion coefficient of the magnetic body portion are different from each other. Therefore, if the dielectric body portion and the magnetic body portion are directly jointed to each other without any intermediate part, the jointed dielectric and magnetic body portions are sintered, and the sintered dielectric and magnetic body portions are cooled, there is a possibility that cracking is generated in a joint area between the dielectric body portion and the magnetic body portion at this cooling stage, and there is a possibility that the dielectric body portion and the magnetic body portion are detached from each other. Thus, in Patent Document 1, glass is used as the material of the intermediate part, which realizes a thermal expansion coefficient of the intermediate part so as to absorb a difference between contraction of the dielectric body portion and contraction of the magnetic body portion at the cooling stage of the sintered dielectric and magnetic body portions.
A composite electronic component is also described in Patent Document 2. The composite electronic component is also formed by jointing a dielectric body portion and a magnetic body portion via an intermediate part. In the composite electronic component as well, plural pairs of electrodes including conductive bodies are provided inside of the dielectric body portion, the dielectric body portion functions as a capacitor, a coil including a conductive body is formed inside of the magnetic body portion, and the magnetic body portion functions as an inductor. The dielectric body portion of the composite electronic component described in Patent Document 2 is formed of ceramic such as TiO2 and Ba3O4. Meanwhile, the magnetic body portion of the composite electronic component described in Patent Document 2 is formed of magnetic oxide ferrite. Therefore, as well as the composite electronic component described in Patent Document 1, a thermal expansion coefficient of the dielectric body portion and a thermal expansion coefficient of the magnetic body portion are different from each other in the composite electronic component described in Patent Document 2. Thus, in Patent Document 2, a material in which one of glass, alumina, and ferrite is mixed with a material of the dielectric body portion is used as a material of the intermediate part, which realizes a thermal expansion coefficient of the intermediate part so as to absorb a difference between contraction of the dielectric body portion and contraction of the magnetic body portion at the cooling stage of the sintered dielectric and magnetic body portions.
A composite electronic component is also described in Patent Document 3 (JP4020886B). The composite electronic component is also formed by jointing a dielectric body portion and a magnetic body portion via an intermediate part. In the composite electronic component as well, plural pairs of electrodes including conductive bodies are provided inside of the dielectric body portion, the dielectric body portion functions as a capacitor, a coil including a conductive body is formed inside of the magnetic body portion, and the magnetic body portion functions as an inductor. The dielectric body portion of the composite electronic component described in Patent Document 3 is formed of Ti ceramic, for example. Meanwhile, the magnetic body portion of the composite electronic component described in Patent Document 3 is formed of Ni—Cu—Zn magnetic ferrite, for example. Therefore, as well as the composite electronic component described in Patent Document 1, a thermal expansion coefficient of the dielectric body portion and a thermal expansion coefficient of the magnetic body portion are different from each other in the composite electronic component described in Patent Document 3. Thus, in Patent Document 3, Fe—Zn—Cu nonmagnetic ferrite and zinc borosilicate glass are used as materials of the intermediate part, which realizes a thermal expansion coefficient of the intermediate part so as to absorb a difference between contraction of the dielectric body portion and contraction of the magnetic body portion at the cooling stage of the sintered dielectric and magnetic body portions.
In such a way, in Patent Documents 1 to 3, for jointing the dielectric and magnetic body portions having different thermal expansion coefficients from each other, the dielectric body portion and the magnetic body portion are jointed via the intermediate part having the thermal expansion coefficient so as to absorb the difference between the contraction of the dielectric body portion and the contraction of the magnetic body portion at the cooling stage of the sintered dielectric and magnetic body portions, so that the dielectric body portion and the magnetic body portion are favorably jointed.